To crimp or not crimp, that is the question...

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tiny68

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....I am trying to answer. I never crimp my 44 Mags. I did a bunch of test years ago with my 308 and 223 bolt rifle and found it made little different in the accuracy. I am setting to start reloading for 40 S&W to feed my Glock 23 and Beretta M96. So.... do I need to by the Lee Deluxue die set with the crimp or the standard set without the crimp. What do you in an autoloader pistol? Any chance of recoil moving the bullet in the case?

Thanks, Tim
 

Shadowrider

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You need to taper crimp auto cartridges, they headspace on the mouth. Just adjust them to remove the belling plus about .001" more and you are good.

Straight walled cartridges are different animals from bottle neck rifle cartridges which usually don't need crimped.
 

Glocktogo

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No crimp on semi-auto pistol cartridges can cause bullet setback when they hit the feed ramp, causing dangerous overpressure. Always crimp them where a firm push against the reloading bench will not shorten the OAL.
 

338Shooter

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I don't usually bell the case mouth if the bullets I'm seating have a boat tail. No need to crimp these. The taper crimp on an auto cartridge just removes the belling you did to it so it will feed reliably. There is plenty of bullet tension without taper crimping. If you taper crimp too much the spring back in the brass will cause you to lose bullet tension that can lead to setback. The tension on these is from the resize, not the crimp.

On revolver loads, you'll want to roll crimp the mouth of the case into the cannelure so the bullets don't come out of the case a little during recoil and jam the cylinder up.

At least, that's how I understand it.
 

tiny68

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Just learned that the std Lee seater has an adjustable crimp. I swear I read those instructions 20 yrs ago. I have been running mild crimp on my 44 Mags and not a full roll like factory rounds. Also now know that I can do this with a std die set and don't need to buy the stand-alone crimp die. Tim
 

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